1967 ] 
Levi — Behavior of Sicarius 
327 
palps for sperm filling. Members of the orb weaver genus T'etra- 
gnatha use the haplogyne method of sperm induction (Gerhardt, 
1927), although the absence of an epigynum in Tetragnatha is be- 
lieved secondary. Filistata, though it lacks an epigynum, is considered 
(there abides a controversy) to belong to a separate line of evolution 
because of the presence of a cribellum. The Filistata male alternates 
the pedipalps in mating and in sperm induction, as do the orthognaths 
(Gerhardt, 1930). 
There is little literature on the significance of longevity of spiders. 
But it is striking that spiders with genitalia considered primitive are 
long lived, those with more typical genitalia are short lived. A short 
life span of one or two seasons and rapid succession of generations 
must be of selective advantage, as it is a charateristic of the most suc- 
cessful groups of spiders. Selective advantages might be larger num- 
bers of progeny, increased number of generations, and ability to 
colonize new situations, especially areas with short seasons, etc. 
Table I summarizes the available data on longevity of spider species 
with simple genitalia. 
Primitive groups of hypochilid spiders, however, are short lived. 
Adult Hypochilus gertschi disappear in the fall, adult females re- 
appearing in July. Probably it takes two years to mature (W. Shear, 
in letter). During an autumn visit to Chile (March, 1965), only 
juveniles of Thaida peculiaris (— A ustrochilus manni ) were found, 
no adults. 
Adult Orthoganatha (e.g. Theraphosidae) molt once or twice a 
year during most of their long lives, except during the last year or 
two. Haplogyne spiders do not molt after reaching maturity. In 
molting, presumably, spiders shed also the lining of the seminal re- 
ceptacles and with it any stored sperm. Thus, it is rare for a captive 
theraphosid to produce an egg sac unless the animal is a recent 
captive. In contrast, some haplogyne females even after years of 
captivity may still produce fertile egg sacs from previous matings. 
Another specialization of scytodids that separates the family from 
other groups should be pointed out. On the venter behind the gono- 
pore the female has sclerotized grooves into which the fangs of the 
male are usually inserted to hold the female during mating; this 
structure is not present in sicariids or loxoscelids. Perhaps these 
grooves represent a preadaptation toward the evolution of an epigy- 
num (the plate bearing separate copulatory pores which lies in front 
of the gonopores) present in most higher spiders. 
